Comparison and assessment of the different methods of synthesis of 18F-FDG
Literature sources indicate that presently 18F-FDG is the most effective PET radiopharmaceutical and that it is used in more than 90% of the cases in diagnostic procedures. The most likely reason for the progressive development of the clinical PET trials over the last 25 years is the huge advancement in the synthesis and the quality control of 18FFDG. The purpose of this overview is to review, compare, and assess the methods of synthesis and the established procedures for quality control of 18F-FDG – the most commonly used pharmaceutical in positron emission tomography. There are two general methods of synthesis of 18F-FDG: electrophilic fluorination and nucleophilic fluorination. We concluded from this overview that the nucleophilic
fluorination reaction is a much more suitable, convenient andpreferable method of synthesis of 18F-FDG, in comparison to electrophilic fluorination. In nucleophilic substitution reactions mannose triflate is used as a precursor molecule, and Cryptofix 2.2.2. is used as а catalyst. These reagents produce the most effective results in the synthesis of 18F-FDG thanks to their
high practical yield (about 80%) by which the finished product is derived, as well as their relatively short reaction time. The synthesizing modules which are very effectively applied in the manufacturing of 18F-FDG, serve as a platform for the development of other similar modules for the other methods ofsynthesis of PET radiopharmaceuticals. The quality control requirements may be found in various pharmacopoeia editions: European Pharmacopoeia, United States Pharmacopoeia, British Pharmacopoeia, the Chemistry, Manufacturing, and Controls issued by the U.S.Food and Drug Administration, as well as in other approvedand reliable sources.We must note that the requirements, procedures, and the acceptable limits vary from one source to another. Eachcountry is entitled to adopt its own standards for quality control of 18F-FDG on the basis of the said pharmacopoeia editions.
|Key words: 18 F-FDG. ELECTROPHILIC FLUORINATION, NUCLEOPHILIC FLUORINATION. QUALITY CONTROL|